The technical sector of the present invention is that of methods for washing a window of a vehicle, in particular a motor vehicle, by using a system for wiping and washing said window. A system of this type is more particularly designed to be installed on a windscreen of the vehicle.
Motor vehicles are commonly equipped with a wiping installation and washing system in order to ensure wiping and washing of the windscreen and to prevent the driver's view of his/her environment from being disrupted. An installation of this type generally comprises two wiper blades which scrape the outer surface of the windscreen, so as to discharge the water which is present on this surface.
For the purpose of washing the windscreen, in particular in the absence of rain, systems of this type are equipped with a reservoir containing a cleaning liquid, known as the first liquid, of a piping system which connects the reservoir to orifices via which the first liquid can be ejected onto the windscreen, and with a pump which can circulate the first liquid in the piping system until it is expelled via the orifices onto the windscreen.
For the purpose of improving the quality of the cleaning, particularly in the case when the windscreen is very dirty, and/or in order to add other functions to the cleaning system, such as, for example, de-icing of the windscreen, it is known to provide a second reservoir containing an active liquid, known as the second liquid, with better cleaning properties and/or de-icing properties. Active liquids of this type are more costly than the conventional cleaning liquids.
The two reservoirs can each have their pump, but they are connected to the same piping system which conveys the first and second liquids to the orifices via which they are ejected onto the windscreen. Thus, when it is wished to change from spraying one of the liquids onto the windscreen to spraying the other one of the liquids, the pump which was functioning is deactivated and the other pump is activated.
A disadvantage is derived from the fact that, when one pump is deactivated and the other one is activated, the activated pump will circulate a first liquid in the piping system, which will drive the second liquid which has remained in the system, as far as the ejection orifices. Second liquid which is not required will therefore be ejected onto the windscreen before the first liquid, which is not economical. In addition, if the windscreen wipers are put into motion as soon as the pump is activated, the first liquid will reach the windscreen in a manner which is offset relative to the functioning of the wiper blades.